Lyme disease is the most prevalent vector-borne disease in the U.S., with about 30,000 cases per year reported by CDC and a range now covering 24 states. Early diagnosis and treatment of Lyme disease is important to prevent the disease from progressing to a systemic infection characterized by chronic arthritis, carditis or neurological disorders. Where a patient does not truly have Lyme disease, an accurate negative test result would be valuable in promptly directing a physician to seek other causes of illness and hopefully minimize unnecessary antibiotic therapy. No Lyme rapid test suitable for physician's office use is commercially available, and the current laboratory-based two-tier Lyme testing algorithm (ELISA followed by Western blot) suffers from high cost, slow time to results (2-5 days), subjective interpretation and low sensitivity for early infections. Accordingly, there s a critical need for a rapid Lyme diagnostic test with improved performance. The overall objective of the proposed project is the development and clinical validation of a rapid, point-of-care test for Lyme disease that will for the first time make accurate Lyme testing accessible to any physician's office. In Phase I we have developed a prototype Lyme rapid test with 15 minute total turnaround time, which exhibited >99% specificity and sensitivity equal to or greater than that of FDA-cleared ELISA tests in both early and late stage infections. In particular, the Lyme C6/C10 rapid test provided high detection sensitivity for very early Lyme infections (<1 week post-onset of erythema migrans rash), significantly better than several FDA- cleared Lyme ELISA tests. The rapid Lyme test is based on three innovative components: 1) novel detection chemistry with ELISA-equivalent sensitivity, 2) a combination of C6 and C10 synthetic peptide antigens yielding high sensitivity for early infections, and 3) an immunoassay format that overcomes previous limitations of rapid tests for sensitive antibody detection. In Phase II we will optimize and validate the rapid test for both whole blood and serum/plasma samples, to enable its use as a CLIA-waived test in a physician's office environment. Performance of the rapid test will be compared to that of the current two-tier Lyme testing algorithm in prospective and retrospective clinical studies to support a 510(k) submission for FDA clearance. Based on the high sensitivity and specificity which we expect to demonstrate in these studies, we will propose an FDA claim that the Lyme rapid test may substitute for one or both steps of the two-tier protocol. The Lyme C6/C10 rapid test will be the first commercial implementation of our novel rapid test technology, and will, for the first time, enable accurate, same-day Lyme disease diagnostic results which could lead to a basic paradigm shift in the standard protocol for Lyme testing.